Trans-Hudson orogeny

Source: Wikipedia, the free encyclopedia.
North American Craton
(Laurentia).
The North American Craton, also called Laurentia.
Trans-Hudson orogen and the Wyoming, Superior and Hearne cratons

The Trans-Hudson orogeny or Trans-Hudsonian orogeny was the major

continents
. The event occurred 2.0–1.8 billion years ago.

The Trans-Hudson orogen sutured together the

intrusions.[1]

The THO is a right-angled

Yavapai province (see Trans-Hudson Orogen map[2] and the THOT Transect map.[3] To the south, the orogen contributed to the subsurface Phanerozoic strata in Montana and the Dakotas that created the Great Plains
.

Overview

The Trans-Hudson orogeny was the culminating event of the Paleoproterozoic Laurentian assembly, which occurred after the Wopmay orogeny (West of Hudson Bay, ca. 2.1-1.9 Ga.). The Trans-Hudson orogeny resulted from the collision of the Superior Craton of eastern Canada with the Hearne Craton in northern Saskatchewan and the Wyoming Craton of the western United States, with the Archean microcontinent Sask Craton trapped in the THO western interior. Similar to the Himalayas, the Trans-Hudson orogeny was also the result of continent-continent collision along a suture zone. Only the roots of this mountain chain remain, but these can be seen in northeastern Saskatchewan and in the Black Hills of South Dakota. The Trans-Hudson orogeny and the consequent upheaval of the continental crust in the middle Proterozoic eon caused the area around the Great Lakes to become a flattened plain, which in turn led to the creation of the intracontinental basin and the interior and central plains of the United States (the Great Plains are the westernmost portion of North America's Interior Plains, which extend east to the Appalachian Plateau).

The Black Hills of South Dakota is one of the few remaining exposed portions of the Trans-Hudson orogenic belt. The peaks of the Black Hills are 3,000 to 4,000 feet above the surrounding plains, while Black Elk Peak - the highest point in South Dakota - has an altitude of 7,242 feet above sea level.[4] These central spires and peaks all are carved from granite and other igneous and metamorphic rocks that form the core of the uplift. The nature and timing of this portion of the THO event in southern Laurentia is poorly understood, when compared to the exposed northern segments in Canada. The Black Hills offer the only surface exposure of the deformed and metamorphosed belt of Paleoproterozoic continental margin rocks in the collisional zone between the Archean Wyoming and Superior provinces. Based on geophysical evidence, this zone has been broadly interpreted to be the southern extension of the THO that was later truncated by the ~1.680 Ga. Central Plains orogen.[5]

Sequence of events

Marine evidence indicates that the area initially opened to form an ocean called the

Volcanic arcs
developed as the cratons collided, eventually resulting in the THO mountain building (orogeny).

Northwestern hinterland zone

The Northwestern hinterland zone is a complex tectonically deformed region that includes the Peter Lake, Wollaston, and Seal River domains, and other parts of the Cree Lake Zone, now included in Hearne Province.

Reindeer zone

The Reindeer zone to the north is a 500 km wide collage of Paleoproterozoic (1.92-1.83 Ga) arc volcanic rocks, plutons, volcanogenic sediments, and younger molasse, divisible into several lithostructural domains. Most of these rocks evolved in an oceanic to transitional, subduction-related arc setting, with increasing influence of Archean crustal components to the northwest. The zone overlies Archean basement exposed in structural windows that are now recognized as the Sask craton.

Wathaman-Chipewyan batholith

The Wathaman-Chipewyan batholith is an Andean-type continental-margin, magmatic arc emplaced 1.86-1.85 Ga.

Flin Flon domain

The Flin Flon domain is in the center of the Trans-Hudson Suture Zone and extends over the border of the Manitoba-Saskatchewan segment east and west. It is west of the Superior Craton, south of the Kisseynew Domain, and east of the Glennie Domain.

Superior Boundary zone

The Superior Boundary zone is a narrow, southeastern, ensialic foreland zone bordering Superior Craton, comprising the Thompson Belt, Split Lake Block, and Fox River Belt.

Economic geology

The Flin Flon greenstone belt is one of the largest Proterozoic volcanic-hosted massive sulfide (VMS) districts in the world, containing 27 Cu-Zn- (Au) deposits from which more than 183 million tonnes of ore have been mined. Most of mined VMS deposits in the Flin Flon belt are associated with juvenile arc volcanic rocks providing a powerful focus for future explorations. Gold mineralization has been less studied, but at Reed Lake has been shown to be associated with late brittle-ductile shear zones that follow peak tectonic and metamorphic activity within the Trans-Hudson Orogen. At Snow Lake, preliminary investigations suggest a long history of gold mineralization with at least some gold introduced prior to metamorphism.[6]

See also

References

  1. ^ M. Stauffer (2006). "Trans-Hudson Orogen". The Encyclopedia of Saskatchwen. Archived from the original on 2017-06-27. Retrieved 2008-01-27. Retrieved on 2008-02-11
  2. ^ Canadian Plains Research Center Mapping Division (2006). "Location of the Trans-Hudson Orogen" (PDF). Canadian Plains Research Center Mapping Division. {{cite journal}}: Cite journal requires |journal= (help) Retrieved on 2008-02-11
  3. ^ Canada's National LITHOPROBE Geoscience Project (1998). "Transects". Canada's National LITHOPROBE Geoscience Project. Archived from the original on 2012-07-18. Retrieved 2012-07-18. {{cite journal}}: Cite journal requires |journal= (help)
  4. ^ Trimble, Donald E. (2008). The Geological Story of the Great Plains - Geological Survey Bulletin 1493 (A nontechnical description of the origin and evolution of the landscape of the Great Plains). United States Government Printing Office, Washington 2004. Archived from the original on 2009-03-05. Retrieved on -02-04
  5. ^ Hill, Joseph C., Nabelek, Peter and Robert Bauer (2008). "Differential Deformational History of Fault-Bounded Blocks: "Southern Trans-Hudson" Orogen, Black Hills, South Dakota". 2004 Denver Annual Meeting (November 7–10, 2004), Paper No. 244-12. Denver, Colorado.{{cite journal}}: CS1 maint: multiple names: authors list (link) Retrieved on -01-28
  6. ^ Bailes, Alan & Ric Syme (2001). "Trans-Hudson Orogen Overview". WILDCAT Explorations LTD. Archived from the original on 2007-05-14.